It is frequently necessary to insert drain (overflow) or venting hoses into cavities of a conveyance, especially a motor vehicle body which may not be readily accessible and to which access may be only had from an end thereof. Such hoses, therefore, must be fed from the end, e.g. through a wall of the vehicle body, into such cavities and, for that purpose, must have sufficient stiffness or buckling resistance to enable the hose to be fed longitudinally even where such movement is frictionally retarded by walls of the body into proper position.
While I am not aware of any publication describing the provision of such hoses having thin-walled longitudinal ribs extending generally radially from an outer surface thereof, I am aware that such hoses, composed entirely of polyvinylchloride, have been utilized in practice.
More common, however, are smooth-surfaced hoses with low-friction outer surfaces, composed of soft polyvinylchloride having a hardness of substantially 85 to 90 Shore A. These hoses have a limited bendability and sufficient buckling resistance to enable them to be inserted longitudinally from an end of a receiving cavity or space or in a through-the-wall manner. They are used in long motor vehicle body channels or spaces which are not readily accessible from the exterior and can be effectively inserted in the manner described.
However, the smooth-surfaced PVC hoses can chatter against the vehicle body and to avoid this, such hoses have frequently been wound with a self-adhesive felt wrap, especially at those locations at which the noise generation is most pronounced. The use of felt wraps increases the cost of the system and the time which is required to emplace the hose.
The ribbed hoses hitherto employed composed of polyvinylchloride, for example, and having the ribs constituted of the same material as the remainder of the hose, does not solve the problem because the ribs do not reduce the noise generated by chattering and, indeed, frequently impede the through-the-wall or longitudinal insertion mode of positioning the hose.
Indeed, resistance to longitudinal insertion may be so great that such longitudinally ribbed hoses cannot be used in many longitudinal-insertion applications and as a result, in practice, the smooth-walled hose, with its felt wrapping, is more commonly employed.